Overview of modern fancy UNIX desktop systems

Heard about the new fancy GUI stuff but a little clueless about what they all are? Wonder no more.

"In the last few months, there has been a lot of talk about Xgl, compiz, AIGLX et cetera. It seems that "Xgl" has become a synonym for fancy desktop on Linux - but nobody seems to talk about the alternatives or how it all works. I have had a little look into this and am going to summarize it for y'all. I will explain where the following come from and how they work: "